{
  description = "mbrts — real-time JMAP mail delivery";

  inputs.nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";

  outputs = {
    self,
    nixpkgs,
  }: let
    systems = ["x86_64-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin"];
    forAllSystems = nixpkgs.lib.genAttrs systems;
    pkgsFor = system: import nixpkgs {inherit system;};
  in {
    packages = forAllSystems (system: let
      pkgs = pkgsFor system;
    in {
      default = pkgs.callPackage ./nix/package.nix {};
      mbrts = self.packages.${system}.default;
    });

    overlays.default = final: _prev: {
      mbrts = final.callPackage ./nix/package.nix {};
    };

    homeManagerModules.default = import ./nix/module.nix;
  };
}